Composite guidewire

ABSTRACT

Alternative designs, materials and manufacturing methods for guidewires. Some embodiments pertain to a composite guidewire having proximal and distal section, and a connector adapted and configured for permanently joining the proximal section to the distal section. In some embodiments, at least one of the sections is made of a linear-elastic nickel-titanium alloy. Several alternative guidewire tip designs including coiled safety/shaping structures are also disclosed.

RELATED APPLICATIONS

This application is a continuation of co-pending U.S. application Ser.No. 11/323,278, filed Dec. 30, 2005, which is a continuation of U.S.application Ser. No. 10/086,992, filed Feb. 28, 2002, now U.S. Pat. No.7,074,197; which is a continuation-in-part of U.S. application Ser. No.09/972,276, filed Oct. 5, 2001, now U.S. Pat. No. 6,918,882; all ofwhich are incorporated herein by reference.

FIELD OF THE INVENTION

The invention generally pertains to intravascular guidewires.

BACKGROUND OF THE INVENTION

A wide variety of guidewires have been developed for intravascular use.Intravascular guidewires are commonly used in conjunction withintravascular devices such as catheters to facilitate navigation throughthe vasculature of a patient. Because the vasculature of a patient maybe very tortuous, it is desirable to combine a number of performancefeatures in an guidewire. For example, it is sometimes desirable thatthe guidewire have a relatively high level of pushability andtorqueability, particularly near its proximal end. It is also sometimesdesirable that a guidewire be relatively flexible, particularly near itsdistal end. A number of different guidewire structures and assembliesare known, each having certain advantages and disadvantages. However,there is an ongoing need to provide alternative guidewire structures andassemblies.

SUMMARY OF THE INVENTION

The invention provides several alternative designs, materials andmethods of manufacturing alternative guidewire structures andassemblies.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is cross sectional fragmentary view of a guidewire(pre-grinding), including a connection utilizing an overlapping taperedjoint and a tubular connector for joining a proximal section and adistal section of the guidewire;

FIG. 2 is a cross sectional fragmentary view of the guidewire (postgrinding) of FIG. 1;

FIG. 3 is a cross sectional fragmentary view of an alternative guidewire(post grinding), including a connection utilizing an overlapping joint(without a tubular connector) for joining a proximal section and adistal section of the guidewire;

FIG. 4 is a cross sectional fragmentary view of an alternative guidewire(post grinding), including a connection utilizing a butt joint and atubular connector for joining a proximal section and a distal section ofthe guide wire;

FIG. 5 is a cross sectional fragmentary view of an alternative guidewire(post grinding), including a connection utilizing an overlapping jointand a tubular connector for joining a proximal section and a distalsection of the guide wire;

FIGS. 6A-6C are cross sectional fragmentary views of various endportions for use with the guidewire embodiment of FIG. 5;

FIG. 7 is a cross sectional fragmentary view of an alternative guidewireconstruction including a connection similar to that shown in FIG. 2utilizing an overlapping tapered joint and a tubular connector forjoining a proximal section and a distal section of the guidewire, andalso showing a distal tip construction;

FIG. 8 is a cross sectional fragmentary view of another alternativeguidewire construction similar to that in FIG. 7, but including analternative tip construction;

FIG. 9 is a cross sectional fragmentary view of another alternativeguidewire construction similar to that in FIG. 7, but including anotheralternative tip construction;

FIG. 10 is a cross sectional fragmentary view of another alternativeguidewire construction similar to that in FIG. 7, but including anotheralternative tip construction;

FIG. 11 is a cross sectional fragmentary view of another alternativeguidewire construction similar to that in FIG. 7, but including anotheralternative tip construction; and

FIG. 12 is a cross sectional fragmentary view of another alternativeguidewire construction similar to that in FIG. 7, but including anotheralternative tip construction.

FIG. 13 is a cross sectional fragmentary view of another embodiment of aguidewire including an alternative tip construction.

FIG. 14 is a cross sectional fragmentary view of another embodiment of aguidewire including another alternative tip construction,

FIG. 15 is a cross sectional fragmentary view of another embodiment of aguidewire including another alternative tip construction.

FIG. 16 is a cross sectional fragmentary view of another embodiment of aguidewire including another alternative tip construction.

FIG. 17 is a cross sectional fragmentary view of another embodiment of aguidewire including another alternative tip construction.

FIG. 18 is a cross sectional fragmentary view of another embodiment of aguidewire including another alternative tip construction.

FIG. 19 is a cross sectional fragmentary view of another embodiment of aguidewire including another alternative tip construction.

FIG. 20 is a cross sectional fragmentary view of another embodiment of aguidewire including another alternative tip construction.

FIG. 21 is a cross sectional fragmentary view of another embodiment of aguidewire including another alternative tip construction.

FIG. 22 is a cross sectional fragmentary view of another embodiment of aguidewire including another alternative tip construction.

FIG. 23 is a cross sectional fragmentary view of another embodiment of aguidewire including another alternative tip construction.

DETAILED DESCRIPTION OF THE INVENTION

The following description should be read with reference to the drawingswherein like reference numerals indicate like elements throughout theseveral views. The detailed description and drawings illustrate examplesof various embodiments of the claimed invention, and are not intended tobe limiting.

Refer now to FIGS. 1-5 which illustrate cross sectional views of aportion of a guidewire 10 including a connection 20 joining a proximalguidewire section 14 and a distal guidewire section 16. FIG. 1illustrates the guidewire 10 and the connection 20 before a finalgrinding step, and FIG. 2 illustrates the guidewire 10 and theconnection 20 after the final grinding step, which provides a smoothouter profile. The embodiment of FIGS. 1 and 2 utilizes an overlappingtapered joint 12 and a tubular connector 18.

The embodiment of FIG. 3 is similar to the embodiment of FIGS. 1 and 2,except that the connection 20 between the proximal guidewire section 14and the distal guidewire section 16 does not utilize a connector tube18, but rather utilizes a connector material 19. The embodiment of FIG.4 is similar to the embodiment of FIGS. 1 and 2, except that theconnection 20 between the proximal guidewire section 14 and the distalguidewire section 16 does not utilize an overlapping joint 12, butrather uses a butt joint 13. The embodiment of FIG. 5 is also similar tothe embodiment of FIGS. 1 and 2, except that the connection 20 betweenthe proximal guidewire section 14 and the distal guidewire section 16utilizes an overlapping joint 12 that is not tapered.

Those of skill in the art and others will recognize that the materials,structure, and dimensions of the proximal/distal guidewire sections14/16 are dictated primary by the desired characteristics and functionof the final guidewire, and that any of a broad range of materials,structures, and dimensions can be used.

For example, the proximal and distal guidewire sections 14/16 may have asolid cross-section as shown, or a hollow cross-section, and may beformed of any materials suitable for use, dependent upon the desiredproperties of the guidewire. Some examples of suitable materials includemetals, metal alloys, and polymers. In some embodiments, it is desirableto use metals, or metal alloys that are suitable for metal joiningtechniques such as welding, soldering, brazing, crimping, frictionfitting, adhesive bonding, etc. As used herein, the proximal section 14and the distal section 16 may generically refer to any two adjacentguidewire sections along any portion of the guidewire. Furthermore,although discussed with specific reference to guidewires, the inventionmay be applicable to almost any intravascular device. For example, theinvention may be applicable to hypotube shafts for intravascularcatheters (e.g., rapid exchange balloon catheters, stent deliverycatheters, etc.) or drive shafts for intravascular rotational devices(atherectomy catheters, IVUS catheters, etc.).

In some embodiments, the proximal guidewire section 14 may be formed ofrelatively stiff material such as straightened 304v stainless steelwire. Alternatively, proximal portion 14 may be comprised of a metal ormetal alloy such as a nickel-titanium alloy, nickel-chromium alloy,nickel-chromium-iron alloy, cobalt alloy, or other suitable material. Ingeneral, the material used to construct proximal portion 14 may beselected to be relatively stiff for pushability and torqueability.

In some embodiments, the distal guidewire section 16 may be formed of arelatively flexible material such as a straightened super elastic orlinear elastic alloy (e.g., nickel-titanium) wire, or a alternatively, apolymer material, such as a high performance polymer. Alternatively,distal portion 16 may be comprised of a metal or metal alloy such asstainless steel, nickel-chromium alloy, nickel-chromium-iron alloy,cobalt alloy, or other suitable material. In general, the material usedto construct distal portion 16 may be selected to be relatively flexiblefor trackability.

In some particular embodiments, the distal section 16 is a linearelastic nickel-titanium alloy, for example, linear elastic nitinol. Theword nitinol was coined by a group of researchers at the United StatesNaval Ordinance Laboratory (NOL) who were the first to observe the shapememory behavior of this material. The word nitinol is an acronymincluding the chemical symbol for nickel (Ni), the chemical symbol fortitanium (Ti), and an acronym identifying the Naval Ordinance Laboratory(NOL).

Within the family of commercially available nitinol alloys, is acategory designated “linear elastic” which, although is similar inchemistry to conventional shape memory and superelastic varieties,exhibits distinct and useful mechanical properties. By skilledapplications of cold work, directional stress, and heat treatment, thewire is fabricated in such a way that it does not display a“superelastic plateau” or “flag region” in its stress/strain curve.Instead, as recoverable strain increases, the stress continues toincrease in an essentially linear relationship until plastic deformationbegins. In some embodiments, the linear elastic nickel-titanium alloy isan alloy that does not show any martensite/austenite phase changes thatare detectable by DSC and DMTA analysis over a large temperature range.For example, in some embodiments, there are no martensite/austenitephase changes detectable by DSC and DMTA analysis in the range of about−60° C. to about 120° C. The mechanical bending properties of suchmaterial are therefore generally inert to the effect of temperature overthis very broad range of temperature. In some particular embodiments,the mechanical properties of the alloy at ambient or room temperatureare substantially the same as the mechanical properties at bodytemperature. In some embodiments, the use of the linear elasticnickel-titanium alloy for the distal portion 16 allows the guidewire toexhibit superior “pushability” around tortuous anatomy.

In some embodiments, the linear elastic nickel-titanium alloy comprisesin the range of about 50 to about 60 wt. % nickel, with the remainderbeing essentially titanium. In some particular embodiments, thecomposition comprises in the range of about 54 to about 57 wt. % nickel.One example of a suitable nickel-titanium alloy is FHP-NT alloycommercially available from Furukawa Techno Material Co. of Kanagawa,Japan.

In some particular embodiments, the proximal guidewire section 14 isformed from a stainless steel wire having a diameter in the range of0.01 to 0.02 inches, and a length in the range of about 50 to about 110inches, and the distal guidewire section 16 is formed from a linearelastic nitinol wire having a diameter that ranges from a diameter tomatch the diameter of the proximal guidewire section 14 to as small asabout 0.002 inches, and a length in the range of 3 to 15 inches.

The distal end 24 of the proximal portion 14 and the proximal end 26 ofdistal portion 16 (i.e., the joined ends) may form an overlappingtapered joint 12 as shown in FIGS. 1-3. Alternatively, the joined ends24/26 may form a butt joint 13 as shown in FIG. 4. As a furtheralternative, the joined ends 24/26 may form an overlapping joint 12 thatis not tapered as shown in FIG. 5. The non-tapered end portions 24/26may have a uniform profile (diameter) 23 as shown in FIG. 6A, a bulbousportion 25 for purposes of mechanical interlocking as shown in FIG. 6B,or a helical form 27 for purposes of mechanical interlocking as shown inFIG. 6C. In each of the embodiments illustrated in FIGS. 1-3 and 5, theend portions 24/26 overlap to form an overlapping joint 12. Theoverlapping joint 12 blends the stiffness of proximal portion 14 anddistal portion 16 by combining the properties of each end section 24/26making up the cross section of the overlapping joint 12. Thus, the joint12 forms a flexibility transition region that has a relative flexibilitythat is between the flexibility of the proximal portion 14 and theflexibility of the distal portion 16.

In the tapered embodiments illustrated in FIGS. 1-3, the ends 24/26 maybe tapered or otherwise formed to have a mating geometry that graduallydecreases in cross sectional area toward the middle of the connection20. The tapered overlapping portion 12 may define a uniform or anon-uniform transition of the sections 24/26, depending on thetransition characteristics desired. For example, the end sections 24/26may be linearly tapered as shown, tapered in a curvilinear fashion, ortapered in a step-wise fashion. If tapered linearly as shown, the angleof the taper may vary. Using the longitudinal center axis of theguidewire 10 as a reference, as measured from the extreme ends of theend sections 24/26, the angle of the taper is acute (i.e., less than 90degrees), and may be in the range of 5 degrees to 45 degrees, forexample. Varying the angle of the tapered ends 24/26 also varies thelength of the overlapping joint 12 in accordance with geometricprinciples. The length of the overlapping joint 12 may be selected toobtain a more (longer length) or less (shorter length) gradualtransition in stiffness.

As mentioned previously, the proximal guidewire section 14 and thedistal guidewire section 16 may be formed of different materials (i.e.,materials having different moduli of elasticity) resulting in adifference in flexibility. For example, the proximal guidewire section14 may be formed of stainless steel wire and the distal guidewiresection 16 may be formed of nickel-titanium alloy wire, both having thesame dimensions, resulting in a 3:1 difference in elastic modulus. Sucha difference in elastic modulus (i.e., flexibility) may result in astress concentration point during flexure and/or torsion that may have atendency to kink and fracture. By virtue of the gradual transition instiffness provided by the overlapping portion 12, stress is distributedalong the entire length of the connection 20 thereby decreasing theprobability that guidewire 10 may kink at the junction.

A gradual transition in stiffness may also allow the connection 20 to belocated further distally. According to this embodiment, the distalportion 16 may be manufactured to be shorter than proximal portion 14.Including a relatively long proximal section 14 may advantageouslyincrease the torquability and pushability of the guidewire 10. Althoughonly one connection 20 is shown, additional connections 20 may be usedto connect other guidewire sections of varying stiffness.

The connector 18 may comprise a tubular structure such as a hypotube asshown or a coiled wire. The connector 18 may have an inside diametersized appropriately to receive the ends 24/26 of the proximal portion 14and the distal portion 16, and an outside diameter sufficient toaccommodate a final grinding procedure. In some example embodiments, theconnector 18 can have an inner diameter in the range of about 0.005 toabout 0.02 inches, and an outer diameter in the range of about 0.01 toabout 0.025 inches. In some particular embodiments, the connector 18 canhave and inner diameter of about 0.010 inches and an outer diameter ofabout 0.014 inches. The final diameter of the guidewire 10 and theconnector 18 may be in the range of 0.010 to 0.018 inches, for example.By way of example, not limitation, the connector 18 may have a length ofabout 1.0 to 3.0 inches for an overlapping portion 12 of about 0.25 to2.5 inches. However, in some other embodiments, this type ofconstruction can be applied to wires of larger diameter intended, forexample, for peripheral intervention purposes. Such wires could range aslarge as 0.035 in diameter and therefore have an extended lengthconnector and correspondingly longer overlapping sections.

The connector 18 may be comprised of a metal or metal alloy, and mayinclude radiopaque materials. Suitable metals and metal alloys includestainless steels, nickel-titanium alloys (e.g., nitinol),nickel-chromium alloys, nickel-chromium-iron alloys, cobalt alloys,nickel, or other suitable materials. Alternatively, connector 18 may becomprised of a polymer or a metal-polymer composite, including aradiopaque filler.

Some types of alloys are particularly suitable for connector 18 forpurposes of connecting a stainless steel proximal section 14 and anickel titanium alloy distal section 16, or visa-versa. An example is anickel-chromium-iron alloy designated UNS N06625 and is available underthe trade name INCONEL 625, which advantageously welds to both stainlesssteels and nickel-titanium alloys. INCONEL 625 wire may be obtained fromCalifornia Fine Wire Company of Grover Beach, Calif., and has thefollowing typical composition: Material Symbol % by wgt Aluminum Al0.140 Carbon C 0.070 Chromium Cr 21.900 Cobalt Co 0.010 Copper Cu 0.030Iron Fe 2.790 Manganese Mn 0.030 Molybdenum Mo 9.150 Nickel Ni 62.000Niobium Nb 3.540 Phosphorus P 0.005 Silicon Si 0.230 Sulfur S 0.009Titanium Ti 0.250 Tantalum Ta 0.010

Another example of a suitable alloy which welds to both stainless steelsand nickel-titanium alloys is designated UNS 10276 and is availableunder the trade name ALLOY C276 from Fort Wayne Metals Research ProductsCorporation of Fort Wayne, Ind., which has the following typicalcomposition: Material Symbol % by wgt Carbon C 0.003 Chromium Cr 15.810Cobalt Co 1.310 Copper Cu 0.100 Iron Fe 5.730 Manganese Mn 0.520Molybdenum Mo 16.010 Nickel Ni 57.000 Phosphorus P 0.008 Silicon Si0.020 Sulfur S 0.005 Tungsten W 3.570 Vanadium V 0.160

Another example of a suitable alloy which welds to both stainless steelsand nickel-titanium alloys is of the Hastelloy family and an example ofwhich is available under the trade name ALLOY B2 from Fort Wayne MetalsResearch Products Corporation of Fort Wayne, Ind., which has thefollowing typical composition: Material Symbol % by wgt Carbon C 0.005Chromium Cr 0.450 Cobalt Co 0.110 Copper Cu 0.030 Iron Fe 1.410Manganese Mn 0.150 Molybdenum Mo 27.720 Nickel Ni 70.000 Phosphorus P0.004 Silicon Si 0.020 Sulfur S 0.002 Tungsten W 0.140

To manufacture the connection 20 of the guidewire 10, the ends 24/26 ofthe proximal and distal guidewire sections 14/16 may be ground to formthe desired shape (e.g., uniform diameter 23, bulbous portion 25, helix27, or taper) to accommodate the overlapping joint 12. If a butt joint13 is to be used, such a shape need not be ground. A recess step may beground into the proximal and distal guidewire sections 14/16 toaccommodate the connector tube 18. If a connector tube 18 is not to beused, such a recess step need not be ground.

For the embodiments utilizing a connector tube 18, the connector tube 18is positioned over one of the ends 24/26 of the proximal and distalguidewire sections 14/16. The distal end 24 of the proximal portion 14and proximal end 26 of the distal portion 16 are then positionedadjacent one another in an overlapping 12 or an end-to-end 13arrangement. The proximal and distal guidewire sections 14/16 and theconnector tube 18 may be bonded, welded (e.g., resistance or laserwelded), soldered, brazed, or otherwise connected by a suitabletechnique depending on the material selected for each component.Alternatively, the ends 24/26 and the connector tube 18 may be crimpedtogether or may be sized to establish a friction fit therebetween. If aconnector tube 18 is not used, the ends 24/26 may be bonded, welded(e.g., resistance or laser welded), soldered, brazed, or otherwiseconnected, using a connector material 19. Connector material 19 may bethe same as or similar to the material of the connector 18. In allcases, because the connection 20 may reside within a catheter lumenduring use, it is preferred that a permanent connection (as opposed to areleasable connection) be used.

It is to be appreciated that various welding processes may be utilizedwithout deviating from the spirit and scope of the present invention.Examples of welding processes which may be suitable in some applicationsinclude LASER welding, resistance welding, TIG welding, microplasmawelding, electron beam, and friction or inertia welding. LASER weldingequipment which may be suitable in some applications is commerciallyavailable from Unitek Miyachi of Monrovia, Calif. and Rofin-SinarIncorporated of Plymouth, Mich. Resistance welding equipment which maybe suitable in some applications is commercially available from PalomarProducts Incorporated of Carlsbad, Calif. and Polaris Electronics ofOlathe, Kans. TIG welding equipment which may be suitable in someapplications is commercially available from Weldlogic Incorporated ofNewbury Park, Calif. Microplasma welding equipment which may be suitablein some applications is commercially available from Process WeldingSystems Incorporated of Smyrna, Tenn.

Once connected, the connector tube 18 and the proximal and distalguidewire sections 14/16 are centerless ground to provide a smooth anduniform profile across the connection 20, and to straighten out smallmisalignments between the proximal and distal guidewire sections 14/16.Other portions of the guidewire 10 may be ground as well to provide thedesired tapers and changes in diameter. For example, one or both of theproximal and distal guidewire sections 14/16 can be continuouslytapered, can have a tapered section or a number or series of taperedsections of differing diameters, or can have a constant diameter. Insome embodiments, the sections 14/16 are tapered or otherwise formed tohave a geometry that decreases in cross sectional area toward the distalend thereof. If tapered, the sections 14/16 can include a uniform or anon-uniform transition of the sections, depending on the transitioncharacteristics desired. For example, one or both of the sections 14/16may be linearly tapered, tapered in a curvilinear fashion, or tapered ina step-wise fashion. The angle of any such tapers can vary, dependingupon the desired flexibility characteristics. The length of the tapermay be selected to obtain a more (longer length) or less (shorterlength) gradual transition in stiffness. Once finally ground, in someembodiments, a flexible coil tip and/or a polymer jacket tip (optionallycovering connection 20) or combination thereof, and other suchstructure, such as radiopaque markers, safety and/or shaping ribbons(coiled or uncoiled), and the like, may be placed on the guidewire 10.Additionally, in some embodiments, a coating, for example a lubricious(e.g., hydrophylic) or other type of coating may be applied to all orportions of the guidewire. Different coatings can be applied todifferent sections of the guidewire. Some examples of such coatings andmaterials and methods used to create such coatings can be found in U.S.Pat. Nos. 6,139,510 and 5,772,609, which are incorporated herein byreference.

The centerless grinding technique may utilize an indexing systememploying sensors (e.g., optical/reflective, magnetic) to avoidexcessive grinding of the connection 20. In some embodiments, thepresence of dissimilar materials in the construction can influence thegrinding technique and tooling used to accomplish uniform materialremoval, create smooth transitions, and successfully bridge acrossadjacent components. In addition, the centerless grinding technique mayutilize a CBN or diamond abrasive grinding wheel that is well shaped anddressed to avoid grabbing the connector 20 during the grinding process.

Refer now to FIG. 7, which shows a cross sectional view of a portion ofa guidewire 110 including a connection 120 similar to the connection 20shown in the embodiment of FIG. 1. The connection 120 utilizes anoverlapping tapered joint 112 and a tubular connector 118 joining aproximal guidewire section 114 and a distal guidewire section 116. Theproximal/distal guidewire sections 114/116, the connection 120, thetapered joint 112, and the tubular connector 118 shown in the embodimentof FIG. 7 can include the same general construction, structure,materials, and methods of construction as discussed above with regard tolike components in the embodiments of FIGS. 1-6C.

The embodiment of FIG. 7 also shows one example of a distal tip portion130 of the guidewire 110 disposed at the distal end portion 134 of thedistal guidewire section 116. The distal end portion 134 includes twotapered regions 142 and 146, and two constant diameter regions 150 and154 such that the end portion 134 has a geometry that decreases in crosssectional area toward the distal end thereof. In some embodiments, thesetapers 142/146 and constant diameter regions 150/154 are adapted andconfigured to obtain a transition in stiffness, and provide a desiredflexibility characteristic.

A wire or ribbon 158 is attached adjacent the distal end 160 of thedistal end portion 134, and extends distally of the distal end portion134. In some embodiments, the wire or ribbon 158 can be a fabricated orformed wire structure, for example a coiled wires, as will be seen inembodiments discussed in more detail below. In the embodiment shown, theribbon 158 is a generally straight wire that overlaps with and isattached to the constant diameter region 154 at attachment point 164. Insome embodiments, the ribbon 158 overlaps with the constant diametersection 154 by a length in the range of about 0.05 to 1.0 inch, but inother embodiments, the length of the overlap can be greater or less.

The ribbon 158 can be made of any suitable material and sizedappropriately to give the desired characteristics, such as strength andflexibility characteristics. Some examples of suitable materials includemetals, metal alloys, polymers, and the like. In some embodiments, theribbon 158 may be formed of a metal or metal alloy such as stainlesssteel, nickel-chromium alloy, nickel-chromium-iron alloy, cobalt alloy,a nickel-titanium alloy, such as a straightened super elastic or linearelastic alloy (e.g., nickel-titanium) wire. The ribbon 158 can beattached using any suitable attachment technique. Some examples ofattachment techniques include soldering, brazing, welding, adhesivebonding, crimping, or the like. In some embodiments, the ribbon or wire158 can function as a shaping structure or a safety structure.

An outer sleeve 168 is disposed about the distal end portion 134 of thedistal guidewire section 116. In the embodiment shown, the sleeve 168extends from the proximal tapered region 142 to beyond the distal mostportion of the ribbon 158, and forms a rounded tip portion 169. In otherembodiments, the sleeve 158 can extend further in a proximal direction,and in some cases can extend over the connection 120, or over theproximal guidewire section 114. In yet other embodiments, the sleeve 168can begin at a point distal of the tapered region 142.

Suitable materials for use as the outer sleeve 168 include any materialthat would give the desired strength, flexibility or other desiredcharacteristics. Some suitable materials include polymers, and likematerial. Examples of suitable polymer material include any of a broadvariety of polymers generally known for use as guidewire polymersleeves. The use of a polymer for outer sleeve 168 can serve severalfunctions. The use of a polymer sleeve can improve the flexibilityproperties of the distal portion 134, Choice of polymers for the sleeve168 will vary the flexibility. For example, polymers with a lowdurometer or hardness will make a very flexible or floppy tip.Conversely, polymers with a high durometer will make a tip which isstiffer. The use of polymers for the sleeve can also provide a moreatraumatic tip for the guide wire. An atraumatic tip is better suitedfor passing through fragile body passages. Finally, a polymer can act asa binder for radiopaque materials, as discussed in more detail below.

In some embodiments, the polymer material used is a thermoplasticpolymer material. Some examples of some suitable materials includepolyurethane, elastomeric polyamides, block polyamide/ethers (such asPebax), silicones, and co-polymers. The sleeve may be a single polymer,multiple layers, or a blend of polymers. By employing careful selectionof materials and processing techniques, thermoplastic, solvent soluble,and thermosetting variants of these materials can be employed to achievethe desired results.

The sleeve 168 can be disposed around and attached to the guidewire 110using any suitable technique for the particular material used. In someembodiments, the sleeve 168 is attached by heating a sleeve of polymermaterial to a temperature until it is reformed around the distalguidewire section 116 and the ribbon 158. In some other embodiments, thesleeve 168 can be attached using heat shrinking techniques. The sleeve168 may be finished, for example, by a centerless grinding or othermethod, to provide the desired diameter and to provide a smooth outersurface.

In some embodiments, the sleeve 168, or portions thereof, can include,or be doped with, radiopaque material to make the sleeve 168, orportions thereof, more visible when using certain imaging techniques,for example, fluoroscopy techniques. Any suitable radiopaque materialknown in the art can be used. Some examples include precious metals,tungsten, barium subcarbonate powder, and the like, and mixturesthereof. In some embodiments, the sleeve 168 can include differentsections having different amounts of loading with radiopaque material.For example, in FIG. 7, the sleeve 168 includes a distal section 170,and a proximal section 172, wherein the distal section 170 has a higherlevel of loading with radiopaque material than the proximal section 172.In some embodiments, it is also contemplated that a separate radiopaquemember or a series of radiopaque members, such as radiopaque coils,bands, tubes, or other such structures could be attached to theguidewire 110, or incorporated into the core wire by plating, drawing,forging, or ion implantation techniques.

Additionally, in some embodiments, a coating, for example a lubricious(e.g., hydrophylic) or other type of coating may be applied overportions or all of the sleeve, or other portions of the guidewire 110.Hydrophobic coatings such as fluoropolymers provide a dry lubricitywhich improves guide wire handling and device exchanges. Lubriciouscoatings improve steerability and improve lesion crossing capability.Suitable lubricious polymers are well known in the art and may includehydrophilic polymers such as polyarylene oxides, polyvinylpyrolidones,polyvinylalcohols, hydroxy alkyl cellulosics, algins, saccharides,caprolactones, and the like, and mixtures and combinations thereof.Hydrophilic polymers may be blended among themselves or with formulatedamounts of water insoluble compounds (including some polymers) to yieldcoatings with suitable lubricity, bonding, and solubility. Some otherexamples of such coatings and materials and methods used to create suchcoatings can be found in U.S. Pat. Nos. 6,139,510 and 5,772,609, whichare incorporated herein by reference. In some embodiments, the moredistal portion of the guidewire is coated with a hydrophilic polymer asdiscussed above, and the more proximal portion is coated with afluoropolymer, such as polytetrafluroethylene (PTFE).

It will be understood by those of skill in the art and others that abroad variety of materials, dimensions, and structures can be used toconstruct suitable embodiments, depending upon the desiredcharacteristics. The following examples of some dimensions for thedistal construction are included by way of example only, and are notintended to be limiting. In some specific embodiments, the guidewire hasthe general structure set fourth in FIG. 7, and the distal guidewiresection 116 has a length in the range of about 10 to 20 inches. The mainportion of the distal guidewire section 116 has an outer diameter in therange of 0.013 to about 0.0145 inches, and the two constant diameterregions 150 and 154 have an outer diameter in the range of about 0.0094to about 0.0097 and in the range of 0.001 to about 0.0014 respectively.The two constant diameter regions 150 and 154 have a length in the rangeof about 4 to about 15 inches and in the range of about 0.5 to about 4inches respectively. The two tapered regions 142 and 146 have lengths inthe range of about 0.5 to about 2.0 inches and in the range of about 0.5to about 2.0 inches, respectively. The polymer sleeve 168 has an outerdiameter sized to match the outer diameter of the main portion of thedistal guidewire section 116, for example in the range of about 0.013 toabout 0.0145 inches. The polymer sleeve distal section 170, is loadedwith a radiapaque material, and has a length in the range of about 1 toabout 3 inches. The ribbon 158 has a length in the range of about 0.8 toabout 2 inches, and in some embodiments can extend about 0.2 to about 1inch distally of the core.

FIG. 8 shows a guidewire 110 very similar to that shown in FIG. 7,wherein like reference numerals indicate similar structure as discussedabove. The proximal/distal guidewire sections 114/116, the connection120, the tapered joint 112, and the tubular connector 118 shown in theembodiment of FIG. 8 can also include the same general construction,structure, materials, and methods of construction as discussed abovewith regard to like components in the embodiments of FIGS. 1-7.

The distal tip portion 130 of the guidewire 110 of FIG. 8 is also verysimilar to that shown in FIG. 7, wherein like reference numeralsindicate similar structure. In the embodiment shown in FIG. 8, however,the ribbon 158 extends further in a proximal direction to overlap withthe tapered region 146, and is attached at two attachment points 164 and165.

Refer now to FIG. 9, which shows a cross sectional view of a portion ofanother embodiment of a guidewire 210 including a connection 220 similarto that shown in the embodiments of FIGS. 7 and 8. The proximal/distalguidewire sections 214/216, the connection 220, the tapered joint 212,and the tubular connector 218 shown in the embodiment of FIG. 9 caninclude the same general construction, structure, materials, and methodsof construction as discussed above with regard to like components in theembodiments of FIGS. 1-8.

The embodiment of FIG. 9 shows another example of a distal tip portion230 of the guidewire 210 disposed at the distal end portion 234 of thedistal guidewire section 216. Like the embodiment of FIG. 7, the distalend portion 234 includes two tapered regions 242 and 246, and twoconstant diameter regions 250 and 254 such that the end portion 234 hasa geometry that decreases in cross sectional area toward the distal endthereof. Additionally, the distal tip portion 230 also includes a wireor ribbon 258 that is attached adjacent the distal end 260 of the distalend portion 234 at attachment point 264 in a similar manner as taughtabove in the embodiment of FIG. 7.

In FIG. 9, however, the distal tip portion 230 includes a combination ofa sleeve 268 and a coil 280 disposed about the distal end portion 234 ofthe distal guidewire section 216. The sleeve 268 extends from theproximal tapered region 242 to a point proximal of the distal end of theguidewire section 216. In the embodiment shown, the sleeve 268 extendsfrom the tapered region 242 to about midway through the tapered portion246. In other embodiments, the sleeve 268 can extend further in aproximal direction, and in some cases can extend over the connection220, or over the proximal guidewire section 214. In yet otherembodiments, the sleeve 268 can begin at a point distal of the taperedregion 242.

The sleeve 268 can be made of and include the same materials, structure,radiopaque loading, and coatings, and be made in accordance with thesame methods as discussed above with regard to the embodiments shown inFIGS. 1-8. In the embodiment shown, an adhesive material or pottingcompound 279 is disposed at the distal end 265 of the sleeve 268 aboutthe distal guidewire section 216. However, in other embodiments, theadhesive material or potting compound 279 is not used.

The coil 280 extends from the adhesive material 279 adjacent the distalend 265 of the sleeve 268 to beyond the distal most portion of theribbon 258. The coil 280 is attached to the distal guidewire section 216at its proximal end 281 at attachment point 283 using any suitableattachment technique, for example soldering, brazing, welding, adhesivebonding, crimping, or the like. The distal end 285 of the coil 280 isattached to the ribbon 258 via a rounded tip portion 269. The roundedtip portion 269 can be made of any suitable material, for example asolder tip, a polymer tip, and the like.

The coil 280 may be made of a variety of materials including metals,metal alloys, polymers, and the like. Some examples of material for usein the coil include stainless steel, nickel-chromium alloy,nickel-chromium-iron alloy, cobalt alloy, or other suitable materials.Some additional examples of suitable material include straightened superelastic or linear elastic alloy (e.g., nickel-titanium) wire, oralternatively, a polymer material, such as a high performance polymer.In some embodiments, the coil 280 can be made of a radiopaque materialssuch as gold, platinum, tungsten, or the like, or alloys thereof. Thecoil 280 may be formed of round or flat ribbon ranging in dimensions toachieve the desired flexibility. In some embodiments, the coil 280 maybe a round ribbon in the range of about 0.001-0.015 inches in diameter,and can have a length in the range of about 2 to about 4 inches.

The coil 280 is wrapped in a helical fashion by conventional windingtechniques. The pitch of adjacent turns of coil 280 may be tightlywrapped so that each turn touches the succeeding turn or the pitch maybe set such that coil 280 is wrapped in an open fashion. In theembodiment shown, the coil 280 is wrapped such that the coil 280 has anopen wrap at its proximal end 281, and includes a tightly wrappedportion adjacent the tip 269.

Additionally, in some embodiments, a coating, for example a lubricious(e.g., hydrophylic) or other type of coating similar to that discussedabove may be applied over portions or all of the sleeve 268 and coil280, or other portions of the guidewire 210.

It will be understood by those of skill in the art and others that abroad variety of materials, dimensions, and structures can be used toconstruct suitable embodiments, depending upon the desiredcharacteristics. The examples of some dimensions for the distalconstruction included with reference to FIG. 7 are also suitable for theembodiment shown in FIG. 9.

FIG. 10 shows a guidewire 210 very similar to that shown in FIG. 9,wherein like reference numerals indicate similar structure. Theproximal/distal guidewire sections 214/216, the connection 220, thetapered joint 212, and the tubular connector 218 shown in the embodimentof FIG. 10 can also include the same general construction, structure,materials, and methods of construction as discussed above with regard tolike components in the embodiments of FIGS. 1-9.

The distal tip portion 230 of the guidewire 210 of FIG. 10 is also verysimilar to that shown in FIG. 9, wherein like reference numeralsindicate similar structure. In the embodiment shown in FIG. 10, however,the ribbon 258 extends further in a proximal direction to overlap withthe tapered region 246, and is attached at two attachment points 264 and283.

Refer now to FIG. 11, which shows a cross sectional view of a portion ofanother embodiment of a guidewire 310 including a connection 320 similarto that shown in the embodiments of FIGS. 7-10. The proximal/distalguidewire sections 314/316, the connection 320, the tapered joint 312,and the tubular connector 318 shown in the embodiment of FIG. 11 caninclude the same general construction, structure, materials, and methodsof construction as discussed above with regard to like components in theembodiments of FIGS. 1-10.

The embodiment of FIG. 11 shows another example of a distal tip portion330 of the guidewire 310 disposed at the distal end portion 334 of thedistal guidewire section 316. Like the embodiment of FIGS. 7-10, thedistal end portion 334 includes two tapered regions 342 and 346, and twoconstant diameter regions 350 and 354 such that the end portion 334 hasa geometry that decreases in cross sectional area toward the distal endthereof. Additionally, the distal tip portion 330 also includes a wireor ribbon 358 that is attached adjacent the distal end 360 of the distalend portion 334 at attachment point 364 in a similar manner as taughtabove in the embodiments of FIGS. 7 and 9.

In FIG. 11, however, the distal tip portion 330 includes a dual coil tipconstruction having an outer coil 380 and an inner coil 390 disposedabout the distal end portion 334 of the distal guidewire section 316.

In the embodiment shown, the outer coil 380 extends about the distalguidewire section 316 from the tapered region 342 to beyond the distalmost portion of the ribbon 358. The outer coil 380 is attached to thedistal guidewire section 316 at its proximal end 381 at attachment point383 using any suitable attachment technique, for example soldering,brazing, welding, adhesive bonding, crimping, or the like. The distalend 383 of the coil 380 is attached to the ribbon 358 via a rounded tipportion 369. The rounded tip portion 369 can be made of any suitablematerial, for example a solder tip, a polymer tip, and the like. Theouter coil 380 can be made of the same materials, and have the samegeneral construction and pitch spacing as the coil 280 discussed abovein the embodiments of FIGS. 9 and 10. In some embodiments, the outercoil 280 can extend distally beyond attachment point 393 for a length inthe range of about 2 to about 4 centimeters.

In the embodiment shown, the inner coil 390 is disposed about the distalguidewire section 316 from the tapered region 346 to a spacer element395 adjacent the tip portion 369. In other embodiments, however, thespacer element is not required. The coil 390 is attached to the distalguidewire section 316 at its proximal end 391 at attachment point 393using any suitable attachment technique, for example soldering, brazing,welding, adhesive bonding, crimping, or the like. The distal end 397 ofthe coil 390 is attached to the spacer element 395. The spacer element395 is disposed about the ribbon 358, and can be made of any suitablematerial, for example metal, metal alloy, or a polymer, or the like. Insome embodiments, the spacer is made of a polymer such aspolytetrafluroethylene (PTFE).

The inner coil 390 can be made of the same materials, and have the samegeneral construction and pitch spacing as discussed above with regard tothe coil 280 in the embodiments of FIGS. 9 and 10. In some embodiments,the inner coil 390 is made of a radiopaque wire having a diameter lessthan that of the wire used to make the outer coil 380.

It will be understood by those of skill in the art and others that abroad variety of materials, dimensions, and structures can be used toconstruct suitable embodiments, depending upon the desiredcharacteristics. The examples of some dimensions for the distalconstruction included with reference to FIG. 7 are also suitable for theembodiment shown in FIGS. 9 and 11.

FIG. 12 shows a guidewire 310 very similar to that shown in FIG. 11,wherein like reference numerals indicate similar structure. Theproximal/distal guidewire sections 314/316, the connection 320, thetapered joint 312, and the tubular connector 318 shown in the embodimentof FIG. 12 can also include the same general construction, structure,materials, and methods of construction as discussed above with regard tolike components in the embodiments of FIGS. 1-11.

The distal tip portion 330 of the guidewire 310 of FIG. 12 is also verysimilar to that shown in FIG. 11, wherein like reference numeralsindicate similar structure. In the embodiment shown in FIG. 12, however,the ribbon 358 extends further in a proximal direction to overlap withthe tapered region 346, and is attached at two attachment points 364 and393.

Refer now to FIGS. 13-21, which show a series of alternative tip designsfor use in guidewires which include a coiled or helically shaped portionof wire or ribbon for use as a safety and/or shaping structure. Such tipdesigns using a coiled or helically shaped safety or shaping structurecan be used in a broad variety of guidewire structures. For example,these tip designs can be used in combination with other structuredisclosed herein, such as the connector structures discussed above, orcan be used in other guidewire constructions, for example guidewiresthat do not include such connector structures.

Refer now to FIG. 13, which shows one embodiment of a guidewire 410having a coiled safety and/or shaping structure 458. The guidewire 410includes a core member 413 having a distal portion 416. The core member413, and the distal portion 416 thereof, can include structure asdisclosed above for portions of a guidewire, or can include otherstructure generally known in the art for use in guidewires.Additionally, the core member 413, and the distal portion 416 thereof,can be made using any of the suitable materials discussed above for usein making guidewire members or sections, or can include other materialsgenerally known in the art for use in guidewires. In the embodimentshown, the distal portion 416 of the core member 413 is a solid wirethat has a tip portion 434 including three constant diameter portions450, 452 and 454, and two tapered portions 442 and 446.

The coiled safety and/or shaping structure 458, for example a coiledribbon, a coiled wire, or other such coiled structure, is disposed abouta portion of the core wire 413. In the embodiment shown, the coiledstructure 458 is a coiled ribbon that overlaps with or surrounds aportion of the distal most tapered portion 446 and the distal mostconstant diameter portion 454, and then extends distally from the distalend 460 of the core wire 413.

The coil 458 can be made of any suitable material and sizedappropriately to give the desired characteristics, such as strength andflexibility characteristics. In some embodiments, the attachment of thecoil 458 to the core wire 413 can also influence the characteristics ofthe portion of the core wire 413 overlapped by the coil 458.

Some examples of material for use in the coil 458 include stainlesssteel, nickel-chromium alloy, nickel-chromium-iron alloy, cobalt alloy,nickel-titanium alloy, or other suitable materials. Some additionalexamples of suitable material include straightened super elastic orlinear elastic alloy (e.g., nickel-titanium), or alternatively, apolymer material, such as a high performance polymer. In someembodiments, the coil 458 can be made of a radiopaque materials such asgold, platinum, tungsten, or the like, or alloys thereof. The coil 458may be formed of round or flat ribbon ranging in dimensions to achievethe desired flexibility. In some embodiments, the coil 458 may be around wire in the range of about 0.001-0.015 inches in diameter. In someother embodiments, the coil can be made of a flat or rectangular shapedribbon having a width in the range of about 0.002 to 0.02 inches and athickness in the range of about 0.0005 to about 0.02 inches.

The coil 458 can be attached to the core wire 413 using any suitableattachment technique. Some examples of attachment techniques includesoldering, brazing, welding, adhesive bonding, crimping, or the like. Inthe embodiment shown, the coil 458 is attached at two attachment points464 and 465.

The coil 458 is wrapped in a helical fashion by conventional windingtechniques. The pitch of adjacent turns of coil 458 may be tightlywrapped so that each turn touches the succeeding turn or the pitch maybe set such that coil 458 is wrapped in an open fashion. In someembodiments, the coil can have a pitch of up to about 0.4 inches, insome embodiments a pitch of up to about 0.08 inches, and in someembodiments, a pitch in the range of about 0.01 to about 0.08 inches.The pitch can be constant throughout the length of the coil 458, or canvary, depending upon the desired characteristics, for exampleflexibility. In some embodiments, the pitch of the coil 458 portion thatoverlaps with the core wire 413 is smaller, while the pitch of the coilportion that does not overlap with the core wire 413 is larger. Forexample, in some embodiments, the pitch of the coil portion thatoverlaps with the core wire 413 is in the range of 0.01 to 0.08 inches,for example 0.04 inches, while the pitch of the coil portion that doesnot overlap with the core wire 413 is up to about 0.08 inches. Thesechanges in coil pitch can be achieved during the initial winding of thewire, or can be achieved by manipulating the coil after winding or afterattachment to the guidewire. For example, in some embodiments, afterattachment of the coil 458 to the guidewire, a larger pitch can beachieved on the distal portion of the coil by simply pulling the coil.

The diameter of the coil 458 is preferably sized to fit around and matewith the distal portion of the core wire 413, and to give the desiredcharacteristics. The diameter of the coil 458 can be constant ortapered. In some embodiments, the coil 458 is tapered to mate withtapered sections of the core wire 413. The diameter of the coil 458 canalso include a taper beyond the distal end of the core wire 413, asdesired.

An outer sleeve 468 is disposed about the distal portion 416 of theguidewire 410. In the embodiment shown, the sleeve 468 extends beyondthe distal most portion of the coiled ribbon 458, and forms a roundedtip portion 469. The sleeve 468 can include structures, and be made withthe materials and methods discussed above with regard to sleevestructures.

It will be understood by those of skill in the art and others that abroad variety of materials, dimensions, and structures can be used toconstruct suitable embodiments, depending upon the desiredcharacteristics. The following examples are included by way of exampleonly, and are not intended to be limiting. In some specific embodiments,the guidewire has the general structure set fourth in FIG. 13, whereinthe core wire 413 is a distal portion of a core wire made of linearelastic nickel-titanium alloy, wherein the constant diameter portions450, 452 and 454 are about 0.0097 inches, 0.006 inches, and 0.003 inchesin diameter, respectively. Additionally, the constant diameter portions452 and 454 are about 1 inch and 0.5 inches in length, respectively. Thetapered portions 442 and 446 are about 1 inch and 1.5 inches,respectively. The coil 458 is about 1.5 inches long, is made offlattened stainless steel wire having width and thickness dimensions ofabout 0.005 inches by about 0.001 inches. The coil 458 has a diameterthat is tapered from about 0.0097 inches on its proximal end to about0.003 inches on its distal end, and is attached to the core wire 413 atattachment points 464 and 465 using solder. The coil 458 overlaps thecore wire 413 for about 1.1 inches, and extends distally of the corewire 413 for about 0.4 inches. The pitch of the coil portion thatoverlaps the core wire is about 0.04 inches and the pitch of the coilportion that extends distally of the core wire is about 0.08 inches. Insome such embodiments, the portion of the guidewire where the coil 458overlaps the core wire 413 for about 1.1 inches is plated, for example,with tin plating. The sleeve 468 is a polyurethane sleeve attached aboutthe core wire 413 and coil 458. A hydrophilic coating is then coatedonto the sleeve 468.

Refer now to FIG. 14, which shows a guidewire 410 having a tipconstruction similar to that shown in FIG. 13, wherein like referencenumerals indicate similar structure. The core wire 413 in the embodimentof FIG. 13, however, has a tip portion 434 including one constantdiameter portion 450, and one tapered portion 442, and the coiled ribbon458 is attached around a portion of the tapered portion 442. The otheraspects and components of the embodiment shown in FIG. 14 can includethe same general structure and materials as discussed above with regardto FIG. 13.

In some specific embodiments, the guidewire 413 has the generalstructure set fourth in FIG. 14, wherein the core wire 413 is a distalportion of a core wire made of linear elastic nickel-titanium alloy,wherein the constant diameter portion 450 is about 0.0097 inches indiameter, and the tapered portion 442 is about 3 inches long, ending atthe distal end thereof at a diameter of about 0.003 inches. The coil 458is about 1.5 inches long, is made of flattened stainless steel wirehaving width and thickness dimensions of about 0.005 inches by about0.001 inches. The coil 458 has a diameter that is tapered from about0.0097 inches oh its proximal end to about 0.003 inches on its distalend, and is attached to the core wire 413 at attachment points 464 and465 using solder The coil 458 overlaps the core wire 413 for about 1.1inches, and extends distally of the core wire 413 for about 0.4 inches.The pitch of the coil portion that overlaps the core wire is about 0.04inches and the pitch of the coil portion that extends distally of thecore wire is about 0.08 inches. In some such embodiments, the portion ofthe guidewire where the coil 458 overlaps the core wire 413 for about1.1 inches is plated, for example, with tin plating. The sleeve 468 is apolyurethane sleeve attached about the core wire 413 and coil 458. Ahydrophilic coating is then coated onto the sleeve 468.

Refer now to FIG. 15, which shows a guidewire 410 having a tipconstruction similar to that shown in FIG. 13, wherein like referencenumerals indicate similar structure. The core wire 413 in the embodimentof FIG. 15, however, has a tip portion 434 including two constantdiameter portions 450, and 454, and one tapered portion 442. The coil458 is attached around the constant diameter portion 454. In FIG. 15,the coil 458 is attached at two attachment points 464 and 465 about theconstant diameter portion 454, is not tapered, and does not include asubstantial pitch change along the length of the coil 458. The otheraspects and components of the embodiment shown in FIG. 15 can includethe same general structure and materials as discussed above with regardto FIG. 13.

Refer now to FIG. 16, which shows a guidewire 410 having a tipconstruction similar to that shown in FIG. 15, wherein like referencenumerals indicate similar structure. In the embodiment of FIG. 16,however, the pitch of the coil 458 is lengthened distal to theattachment point 464 as compared to the pitch of the coil 458 proximalto the attachment point 464. The other aspects and components of theembodiment shown in FIG. 16 can include the same general structure andmaterials as discussed above with regard to FIG. 13.

Refer now to FIG. 17, which shows a guidewire 410 having a tipconstruction similar to that shown in FIG. 16, wherein like referencenumerals indicate similar structure. In the embodiment of FIG. 17,however, only attachment point 464 near the distal end of the core wire413 is used. The other aspects and components of the embodiment shown inFIG. 17 can include the same general structure and materials asdiscussed above with regard to FIG. 13.

Refer now to FIG. 18, which shows a guidewire 410 having a tipconstruction similar to that shown in FIG. 16, wherein like referencenumerals indicate similar structure. In the embodiment of FIG. 18,however, only the more proximal attachment point 465 is used. The otheraspects and components of the embodiment shown in FIG. 18 can includethe same general structure and materials as discussed above with regardto FIG. 13.

Refer now to FIG. 19, which shows a guidewire 410 having a tipconstruction similar to that shown in FIG. 16, wherein like referencenumerals indicate similar structure. In the embodiment of FIG. 19,however, the safety and/or shaping structure 458 has a coiled portion490 that is coiled around the constant diameter portion 454, and thentransforms into a non-coiled portion 492 that extends distally from thedistal end of the core wire 413. The other aspects and components of theembodiment shown in FIG. 18 can include the same general structure andmaterials as discussed above with regard to FIG. 13.

Refer now to FIG. 20, which shows a guidewire 410 having a tipconstruction similar to that shown in FIG. 19, wherein like referencenumerals indicate similar structure. In the embodiment of FIG. 20,however, the safety and/or shaping structure 458 includes two separateportions—a generally straight portion 492 that overlaps with theconstant diameter portion 454 and extends distally from the distal endof the core wire 413, and a coiled portion 490 that is coiled aroundboth the straight ribbon portion 492 and the constant diameter portion454 to attach the straight portion 492 to the constant diameter portion454. The other aspects and components of the embodiment shown in FIG. 18can include the same general structure and materials as discussed abovewith regard to FIG. 13.

Refer now to FIG. 21, which is a partial cross sectional view of aguidewire 410 tip construction similar to that shown in FIG. 19, whereinlike reference numerals indicate similar structure. Like the embodimentof FIG. 19, the embodiment shown in FIG. 21 includes a safety and/orshaping structure 458 that has a coiled portion 490 that is coiledaround the constant diameter portion 454, and then safety and/or shapingstructure 458 transforms into a non-coiled portion 492 that extendsdistally from the distal end of the core wire 413. However, in FIG. 21,the non-coiled portion 492 is twisted to form a helix shaped wire. Theother aspects and components of the embodiment shown in FIG. 21 caninclude the same general structure and materials as discussed above withregard to FIG. 13.

Refer now to FIG. 22, which is a partial cross sectional view of aguidewire 410 including a tip construction similar to the distal tipportion 230 of the guidewire 210 shown in FIGS. 9 and 10, wherein likereference numerals indicate similar structure. In the embodiment of FIG.22, however, the tip construction includes a coiled safety and/orshaping structure 458 rather than a non-coiled ribbon 258 as shown ofFIGS. 9 and 10. The coil is attached to the guidewire at two attachmentpoints 464 and 465, for example, through soldering. The other aspectsand components of the embodiment shown in FIG. 21 can include the samegeneral structure and materials as discussed above with regard to FIGS.9 and 10, and/or with regard to FIG. 13.

Refer now to FIG. 23, which is a partial cross sectional view of aguidewire 410 including a tip construction similar to the distal tipportion 230 of the guidewire 210 shown in FIGS. 11 and 12, wherein likereference numerals indicate similar structure. In the embodiment of FIG.23, however, the tip construction includes a coiled safety and/orshaping structure 458 rather than a non-coiled structure 258 as shown ofFIGS. 11 and 12. The coil is attached to the guidewire at two attachmentpoints 464 and 465, for example, through soldering. Additionally, theembodiment of FIG. 21 also does not include an inner coil 390 and aspacer 395 as shown in FIGS. 11 and 12. The other aspects and componentsof the embodiment shown in FIG. 21 can include the same generalstructure and materials as discussed above with regard to FIGS. 11 and12, and/or with regard to FIG. 13.

It should be understood that this disclosure is, in many respects, onlyillustrative. Changes may be made in details, particularly in matters ofshape, size, and arrangement of steps without exceeding the scope of theinvention. For example, alternative structure can be used in connectingthe proximal and distal sections of guidewires. Additionally,alternative tip constructions including a flexible coil tip, a polymerjacket tip, a tip including a coiled safety/shaping wire, or combinationthereof, and other such structure may be placed on the guidewire. Theinvention's scope is, of course, defined in the language in which theappended claims are expressed.

1. A guidewire comprising: an elongate core including a distal portionand a proximal portion, the distal portion comprising a linear elasticnickel-titanium alloy and the proximal portion comprising a metallicmaterial different from the linear elastic nickel-titanium alloy.
 2. Theguidewire of claim 1, wherein the linear elastic nickel-titanium alloydemonstrates no martensite/austenite phase changes detectable by DSC andDMTA analysis over a temperature range of about 60° C. to about 120° C.3. The guidewire of claim 1, wherein the linear elastic nickel-titaniumalloy has stress/strain characteristics such that it does not display asuperelastic plateau or a superelastic flag region in its stress/straincurve.
 4. The guidewire of claim 1, wherein the linear elasticnickel-titanium alloy has stress/strain characteristics such that asrecoverable strain increases, stress continues to increase in asubstantially linear relationship until a plastic deformation begins. 5.The guidewire of claim 1, wherein the linear elastic nickel-titaniumalloy demonstrates mechanical bending properties that remainlinear-elastic over a temperature range of about −60° C. to about 120°C.
 6. The guidewire of claim 1, wherein the linear elasticnickel-titanium alloy demonstrates linear elastic mechanical bendingproperties at both ambient or room temperature and at body temperature.7. The guidewire of claim 1, wherein the linear elastic nickel-titaniumalloy comprises about 50 to about 60 wt. % nickel with the balance beingsubstantially titanium.
 8. The guidewire of claim 1, wherein the linearelastic nickel-titanium alloy comprises about 54 to about 57 wt. %nickel.
 9. The guidewire of claim 1, wherein the guidewire furthercomprises a super elastic nickel-titanium alloy section connected to thedistal portion and extending distally beyond the distal portion.
 10. Theguidewire of claim 11, wherein the distal portion includes a distal end,and the super elastic nickel-titanium alloy section comprises a separatemember attached to the distal end of the distal portion.
 11. Theguidewire of claim 9, wherein the super elastic nickel-titanium alloysection comprises a wire or ribbon comprising a super-elastic material.12. The guidewire of claim 1, wherein the proximal portion and thedistal portion are joined by a connector.
 13. The guidewire of claim 1,wherein the proximal portion comprises stainless steel.
 14. Theguidewire of claim 1, further including a coil member attached to thedistal portion, the coil member extending distally beyond the core andincluding a distal end, and an atraumatic tip attached to the distal endof the coil member.
 15. The guidewire of claim 14, further including anon-superelastic shaping ribbon attached to the distal portion, theshaping ribbon being disposed within the coil member and being attachedto the atraumatic tip.
 16. A medical guidewire comprising: a distalportion comprising a linear elastic nickel-titanium alloy; a proximalportion comprising a metallic material different from the linear elasticnickel-titanium alloy; and a distal section connected to the distalportion, the distal section comprising a super-elastic nickel titaniumalloy.
 17. The medical guidewire of claim 16, wherein the distal sectioncomprises a separate member attached to the distal portion.
 18. Themedical guidewire of claim 17, wherein the distal portion includes adistal end, and the distal section is attached to the distal end of thedistal portion.
 19. The medical guidewire of claim 16, wherein thedistal section comprises a wire or ribbon comprising a super-elasticmaterial.
 20. The medical guidewire of claim 16, wherein the proximalportion comprises stainless steel.
 21. A method of making a guidewire,the method comprising: providing a distal core portion comprising alinear-elastic nickel-titanium alloy, the distal core portion includinga proximal end; providing a proximal core portion comprising stainlesssteel, the proximal core portion having a distal end; and connecting theproximal end of the distal core portion to the distal end of theproximal core portion.
 22. The method of claim 21, wherein a distalsection comprising a super-elastic nickel titanium alloy is connected tothe distal core portion.
 23. The method of claim 22, wherein distalsection comprises a wire or ribbon comprising a super-elastic material.